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CentOS Linux

Information Technology > Operating system

Description

CentOS Linux skills encompass a broad range of technical abilities, starting from basic tasks like navigating the file system and managing files, to intermediate skills such as setting up web servers and managing security with SELinux. As one progresses, advanced skills include network configuration, system security hardening, and performance tuning. Expertise in CentOS involves mastering complex system troubleshooting, automation with tools like Ansible, containerization technologies, and contributing to the open-source community. These skills are acquired progressively, allowing users to manage and optimize CentOS systems effectively, ensuring they are secure, efficient, and capable of serving in high-demand environments.

Expected Behaviors

✎
LEVEL 1

Fundamental Awareness

Individuals at this level have a basic understanding of CentOS Linux. They can navigate the file system, perform simple file manipulations, and understand basic system commands. Their skills are mostly theoretical, gained from introductory tutorials or courses.

🌱
LEVEL 2

Novice

Novices can perform basic system administration tasks such as managing cron jobs, customizing the shell environment, and configuring network settings. They have practical experience but may still need guidance for more complex tasks.

🌍
LEVEL 3

Intermediate

At the intermediate level, users can automate tasks, manage security aspects like SELinux and firewalls, and handle standard system maintenance. They understand system logs for troubleshooting and can manage web servers and RAID arrays.

⭐
LEVEL 4

Advanced

Advanced users are proficient in system and network configuration, security auditing, and performance tuning. They can manage mail servers, secure web hosting, and high availability systems. Their skills also include managing NFS and Samba shares.

🏆
LEVEL 5

Expert

Experts have deep knowledge of CentOS Linux, capable of performance tuning, advanced troubleshooting, and security management. They automate with Ansible, manage containers, and contribute to open source. They plan and execute disaster recovery strategies.

Micro Skills

✎
LEVEL 1

Fundamental Awareness

Using cd to change directories
Listing directory contents with ls
Understanding absolute and relative paths
Opening, reading, and closing files
Inserting, modifying, and deleting text
Saving changes and exiting the editor
Copying files with cp
Moving and renaming files with mv
Deleting files with rm
Using wildcards for file selection
Using find to locate files by name, size, or type
Using grep to search inside files
Combining find and grep for advanced searching
Reading file permission symbols
Changing file permissions with chmod
Changing file ownership with chown
Installing packages with yum install
Updating packages with yum update
Removing packages with yum remove
Listing installed packages and available updates
Creating simple bash scripts
Making scripts executable
Basic bash syntax: variables, loops, and conditionals
Checking the status of firewalld
Starting and enabling firewalld
Adding and removing allowed services
Enabling and disabling ports
Adding and removing users with useradd and userdel
Creating and deleting groups with groupadd and groupdel
Changing passwords with passwd
Modifying user and group memberships
🌱
LEVEL 2

Novice

Understanding cron syntax
Editing crontab files
Scheduling recurring tasks
Viewing and interpreting cron logs
Troubleshooting common cron issues
Setting environment variables
Modifying the bash prompt
Using aliases for commands
Configuring bash profiles (.bashrc, .profile)
Creating hard and symbolic links
Using find to locate files and directories
Executing commands on files found with find
Understanding the differences between hard and symbolic links
Assigning IP addresses
Configuring network interfaces
Managing routes
Testing connectivity with ping and traceroute
Understanding basic DNS settings
Installing Apache, MySQL/MariaDB, PHP
Configuring Apache virtual hosts
Securing MySQL/MariaDB
Testing PHP processing
Managing services with systemctl
Understanding SELinux modes
Changing SELinux modes
Viewing and interpreting SELinux logs
Restoring default file contexts
Troubleshooting common SELinux policy violations
Installing and starting the SSH service
Configuring SSH keys for passwordless login
Securing SSH (changing ports, disabling root login)
Understanding SSH configuration options
Troubleshooting SSH connectivity issues
Monitoring disk usage with df and du
Cleaning up unnecessary files
Managing partitions with fdisk or gdisk
Understanding inode usage
Extending filesystems
Locating and viewing log files (/var/log/)
Understanding syslog and rsyslog
Monitoring logs in real time with tail and less
Configuring log rotation
Identifying common error messages
🌍
LEVEL 3

Intermediate

Configuring third-party repositories
Prioritizing repositories
Creating a local repository
Using rpm and yum to manage individual packages
Understanding yum history and rollback features
Writing basic bash scripts
Using variables and input in scripts
Control structures (if, for, while)
Error handling and debugging scripts
Automating system administration tasks with scripts
Configuring name-based virtual hosts
Configuring IP-based virtual hosts
Securing virtual hosts with SSL/TLS
Optimizing virtual host performance
Troubleshooting common virtual host issues
Understanding SELinux modes and policies
Troubleshooting SELinux policy violations
Customizing SELinux policies
Using audit2allow to generate custom policy modules
Managing SELinux booleans
Understanding RAID levels and their uses
Creating and configuring software RAID arrays
Monitoring RAID array health
Replacing failed disks in a RAID array
Expanding RAID arrays
Planning a backup strategy
Performing manual backups with tar and rsync
Automating backups with cron
Restoring data from backups
Testing backup and recovery processes
Using top, htop, and other monitoring tools
Understanding system load and performance metrics
Identifying resource bottlenecks
Basic kernel tuning with sysctl
Optimizing filesystem performance
Disabling root login over SSH
Using key-based authentication
Changing the default SSH port
Limiting user access via SSH
Implementing SSH banners
Creating custom firewall rules with iptables
Saving and reloading iptables rules
Configuring firewalld zones and services
Port forwarding and masquerading
Implementing rate limiting and blocking IP addresses
⭐
LEVEL 4

Advanced

Understanding sysctl and /proc/sys/
Modifying kernel parameters at runtime
Persisting kernel parameter changes
Tuning virtual memory settings
Adjusting network stack parameters
Managing kernel modules
Configuring advanced routing
Diagnosing network issues with tools like tcpdump and wireshark
Implementing traffic shaping and QoS
Securing network interfaces
IPv6 configuration
Bonding and teaming interfaces
Configuring NFS server and client
Securing NFS
Troubleshooting NFS issues
Setting up Samba as a file server
Integrating Samba with Windows Active Directory
Samba user and group management
Performance tuning for Apache/Nginx
Securing Apache/Nginx with mod_security and similar modules
Reverse proxy and load balancing
Dynamic module management
Advanced URL rewriting and redirection
Integrating caching solutions
Postfix basic configuration
Securing Postfix with TLS
Integrating spam filtering and antivirus
Virtual domain and user setup
Postfix performance tuning
Troubleshooting mail delivery issues
Analyzing and optimizing SQL queries
Configuring and managing database caching
Database indexing strategies
Replication and load balancing
Backup and recovery optimization
Monitoring database performance
Generating and installing SSL certificates
Configuring server for strong encryption
OCSP stapling and HSTS configuration
SSL/TLS performance optimization
Troubleshooting SSL/TLS issues
Integrating Let's Encrypt for automated certificate renewal
Conducting vulnerability scans
Implementing intrusion detection systems
Security benchmarking and compliance testing
Rootkit detection and removal
Hardening services and applications
Implementing mandatory access control with SELinux or AppArmor
Configuring and managing a Pacemaker and Corosync cluster
Setting up a high-availability LAMP stack
Failover strategies and implementation
Load balancing techniques
Cluster resource management
Quorum and fencing configuration
🏆
LEVEL 5

Expert

Using top and htop
Utilizing iotop for IO monitoring
Employing vmstat for system analysis
Applying sar for historical data analysis
Editing sysctl.conf for persistent changes
Using sysctl command for temporary adjustments
Understanding key kernel parameters
Configuring TCP/IP stack
Implementing Quality of Service (QoS)
Benchmarking network performance
RAID configuration and tuning
Filesystem choices and tuning
LVM management for flexibility
Indexing strategies
Query analysis and rewriting
Database server tuning
Implementing reverse proxy solutions
DNS round-robin technique
Using cloud-based load balancers
Web caching with Varnish or Squid
Database caching techniques
Content Delivery Networks (CDN)
Choosing a CDN provider
Configuring CDN for web applications
Monitoring and optimizing CDN performance

Skill Overview

  • Expert2 years experience
  • Micro-skills198
  • Roles requiring skill1

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